My RX7SP build up

[RICE RACING]

Originally Posted by Prodigy

Did you modify the size/shape of the tub on the rotor to lower compression? Looks like you increased the area and depth of it...


J.

YES, it is the only way to cure the FUCKED Mazda casting and equalize the CR on each face, but most importantly to run the correct CR needed for highest power and reliable operation.

If you look at the old Honda F1 turbo days (running 84% Methyl benzene fuel)
2.5bar (22psi engine) ran 9.5:1 CR
4.0bar (43psi engine) ran 7.4:1 CR
It's all about using the right CR to stay within the effective compression ratio guidelines I posted above in my spreadsheet.
early pump fuel turbo engines ran 6.5:1 CR
Mazda Factory 13B bridge turbo's and the same motors sent to RB ran 7.5:1 CR

Its not Rocket Science, just basic Thermodynamics and laws being respected.

My CR is not openly disclosed but you can guess it's near these correct figures